Clean and wash the kohlrabis. Wash and peel potatoes thoroughly. Dice both roughly. Peel and chop the onion. Heat oil in a pot, fry onion and potatoes in it at medium heat, add kohlrabis, fry briefly and deglaze with broth. Bring to the boil and simmer at low heat for about 18 minutes. In the meantime clean, wash and quarter the tomatoes.
Remove the soup from the heat, take 2 tablespoons of kohlrabi cubes from the stock and set aside. Puree the remaining kohlrabi and potatoes in the stock with a blender. Stir in cream, bring to the boil again and season to taste with salt, pepper and sugar. Cut kohlrabi cubes aside a little bit smaller. Add tomatoes to the soup. Cut cress from the bed. Serve the soup in deep plates sprinkled with cress and kohlrabi cubes
own requi.: cloth, trowel